Wide bandgap semiconductors show superior material properties enabling potential power device operation at higher temperatures, voltages, and switching speeds than current Si technology. As a result, a new generation of power devices is being developed for power converter applications in which traditional Si power devices show limited operation. The use of these new power semiconductor devices will allow both an important improvement in the performance of existing power converters and the development of new power converters, accounting for an increase in the efficiency of the electric energy transformations and a more rational use of the electric energy. At present, SiC and GaN are the more promising semiconductor materials for these new power devices as a consequence of their outstanding properties, commercial availability of starting material, and maturity of their technological processes. This paper presents a review of recent progresses in the development of SiC- and GaN-based power semiconductor devices together with an overall view of the state of the art of this new device generation.

A Survey of Wide Bandgap Power Semiconductor Devices

Wireless power transfer (WPT) using magnetic resonance is the technology which could set human free from the annoying wires. In fact, the WPT adopts the same basic theory which has already been developed for at least 30 years with the term inductive power transfer. WPT technology is developing rapidly in recent years. At kilowatts power level, the transfer distance increases from several millimeters to several hundred millimeters with a grid to load efficiency above 90%. The advances make the WPT very attractive to the electric vehicle (EV) charging applications in both stationary and dynamic charging scenarios. This paper reviewed the technologies in the WPT area applicable to EV wireless charging. By introducing WPT in EVs, the obstacles of charging time, range, and cost can be easily mitigated. Battery technology is no longer relevant in the mass market penetration of EVs. It is hoped that researchers could be encouraged by the state-of-the-art achievements, and push forward the further development of WPT as well as the expansion of EV.

Wireless Power Transfer for Electric Vehicle Applications

DC-link capacitors are an important part in the majority of power electronic converters which contribute to cost, size and failure rate on a considerable scale. From capacitor users' viewpoint, this paper presents a review on the improvement of reliability of dc link in power electronic converters from two aspects: 1) reliability-oriented dc-link design solutions; 2) conditioning monitoring of dc-link capacitors during operation. Failure mechanisms, failure modes and lifetime models of capacitors suitable for the applications are also discussed as a basis to understand the physics-of-failure. This review serves to provide a clear picture of the state-of-the-art research in this area and to identify the corresponding challenges and future research directions for capacitors and their dc-link applications.

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Reliability of Capacitors for DC-Link Applications in Power Electronic Converters—An Overview

Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper.

https://ieeexplore.ieee.org/ielaam/41/8031005/7815312-aam.pdf

Review of Silicon Carbide Power Devices and Their Applications

Gallium nitride (GaN) power devices are an emerging technology that have only recently become available commercially. This new technology enables the design of converters at higher frequencies and efficiencies than those achievable with conventional Si devices. This paper reviews the characteristics and commercial status of both vertical and lateral GaN power devices, providing the background necessary to understand the significance of these recent developments. In addition, the challenges encountered in GaN-based converter design are considered, such as the consequences of faster switching on gate driver design and board layout. Other issues include the unique reverse conduction behavior, dynamic $R_{\mathrm {{ds}},\mathrm {{on}}}$ , breakdown mechanisms, thermal design, device availability, and reliability qualification. This review will help prepare the reader to effectively design GaN-based converters, as these devices become increasingly available on a commercial scale.

Review of Commercial GaN Power Devices and GaN-Based Converter Design Challenges

A novel packaging structure of a power module is developed, which integrates direct liquid cooling for power semiconductor devices through bonding of power stage and a unique cold base plate. By using this technology and combining the attributes of SiC power semiconductor switches, an advanced power module, featuring low power losses and high cooling efficiency, have been produced. Directly compared to a silicon (Si) counterparts and conventional packaging, the advantages of this SiC module packaging in cost-effectiveness, power conversion efficiency, power density for power electronics systems have also been demonstrated.

Advanced packaging of SiC power module for automotive applications

Taking full advantage of SiC devices, a team from Oak Ridge National Laboratory, the University of Tennessee and Virginia Polytechnic Institute and State University have designed, developed, and tested a phase-leg power module based on a high temperature wirebond package. Details of the layout, gate drive, and cooling system designs are described. Continuous power tests confirmed that our design process produced a high density power module that operated successfully at high junction temperatures.

250°C SiC high density power module development

In this article, a practical electrothermal SPICE model is proposed based on finite differential method. Other than the conventional Fourier model and the Hefner model, the distribution of excess carriers can be accurately solved by a finite differential method in the SPICE simulation tool. In this method, the electrothermal behavior of the device is modeled by using a semi-mathematic model. In order to verify the modeling results, a self-packaging insulated-gate bipolar transistor (IGBT) module is tested in both static characteristics and dynamic characteristics, and the simulation results of the presented model fit well with the experimental results under different junction temperatures. More importantly, the finite differential method provided in this article is an approach for modeling bipolar devices, and it can also be applied to model widebandgap devices such as a SiC IGBT and a SiC BJT.

An Electrothermal Model for IGBT Based on Finite Differential Method

This study confirms that high stresses between the metallization layer and ceramic lead to significant failures in DBC substrate. The driving forces behind several different failure modes are discussed. Further understanding of these failure mechanisms enables the modules to be engineered for longtime operation and helps to enhance the reliability of system-level operation.

Thermomechanical reliability investigation of large temperature excursions in power electronics packages

Provided is an IGBT junction temperature measuring device. A power supply circuit of the device is connected with a DSP controller, a voltage collection circuit, a current collection circuit, a voltage reference circuit, a signal processing circuit and an isolation circuit; the two ends of the voltage collection circuit are connected with a measured IGBT and a signal processing circuit respectively; the two ends of the current collection circuit are connected with the DSP controller and the measured IGBT respectively; the voltage reference circuit is connected with the signal processing circuit; the signal processing circuit is connected with the voltage collection circuit, the voltage reference circuit and the isolation circuit; and the two ends of the isolation circuit are connected with the signal processing circuit and the DSP controller respectively. According to the invention, the switching-off delay time tdoff of the IGBT and the collector current of the IGBT are measured in real time, and the present junction temperature of the IGBT can be obtained according to three-dimensional relation among the junction temperature, collector current and switching-off delay time tdoff of the IGBT.

Puqi Ning

Papers

Advanced packaging of SiC power module for automotive applications

250°C SiC high density power module development

An Electrothermal Model for IGBT Based on Finite Differential Method

Thermomechanical reliability investigation of large temperature excursions in power electronics packages

IGBT junction temperature measuring device